Earth boring tool



Feb., 28, 1950 G. MICHAEL EARTH BORING TooL Filed Dec. 26, 1947 Gurney l.. Michael INVEN TOR.

Patented Feb, 28, 195@ UNITED STA'IES 1 Claim.

This invention relates to new and useful improvements and structural refinements in earth boring tools, and the principal object of the invention is to provide a device of the character herein described,such as may be conveniently and effectively employed for the drilling or boring of shafts in the ground preparatory to the installation fof well casings,

A further object ofthe invention is to provide an earth boring tool which is simple in construction, which may be easily and conveniently manipulated, and which may be readily applied to or removed from the work. y

Another object of the invention is to provide an earth boring tool which will not easily become damaged, which will readily lend itself to economical manufacture, and which is otherwise `Well adapted for the purpose for which it is intended.

With the above more important objects in view, and such other objects as may become apparent as this speciiication proceeds, the invention oonsists essentially of the arrangement and construction of parts as illustrated in the accompanying drawing, in which- Figure l is an elevational view of the invention, the same being shown in situ in a well casing;

Figure 2 is a cross sectional view, taken substantially in the plane of the line 2--2 in Figure Figure 3 is a bottom plan view, taken in the plane of the line 3 3 in Figure 2;

Figure 4 is a cross sectional view, taken substantially in the plane of the line -l in Figure 1, and;

Figure 5 is a cross sectional View, taken substantially in the plane of the line 5 5 in Figure 4.

Like characters of reference are employed to designate like parts in the specication and throughout the several Views.

Referring now to the accompanying drawing in detail, the invention consists of an earth boring tool designated generally by the reference character l0, the same embodying in its construction a rotatable, vertically disposed drive shaft Il, adapted for positioning within the usual well casing l2.

A lower end portion of the shaft ll projects below the lower end of the casing, and a cutter i head I3 is rigidly secured to the lower end por tion of the shaft by means of a transversely extending pin I4.

The underside of the head i3 is provided with a plurality of radially disposed slots l5, wherein a plurality or" radially projectible and'retractable cutters le are pivotally mounted by means `of suitable pins ll.

It will be observed that the outer diameter of the cutter head i3 is somewhat smaller with respect to the inner diameter of the casing I2, so that an annular space exists between the casing and the cutter head, to facilitate free rotation of the latter.

The lower end portion oi the shaft Il projects below the underside of the cutter head and terminates in a pointed extremity i8, and the lower end ,portion of the shaft is also formed with a plurality of concave recesses t9 which slidably receive convex inner extremities 2li of the cutters i6, when the cutters are in their radially projected positions, as indicated in Figure 2;

The outer ends of the cutters I6 are provided with a plurality of teeth 2l, matters being so arranged that when the cutters are radially projected, the teeth 2l extend beyond the periphery of the casing l2, substantially as shown.

The cutters it; are supported in their radially projected positions by abutting against downwardly extending wall portions 22 formed at the outer edges of the slots te of the cutter head l 3, and the cutters are normally urged in engagement with the wall portions by means of arcuate compression springs 23. These springs are disposed within the slots l5, one end of each spring being seated in a notch Ell formed in the cutter, while the remaining end of the spring engages the inner surface of the aforementioned wall portion 22, as indicated at 25.

It will be apparent that by virtue of this arrangement the cutters will be normally disposed in radially projected positions, but may be retracted against the resiliency of the springs 23, to a position indicated by the horizontal lines The shaft El and the cutter head i3 are centered, so to speak, in the casing l2, this being accomplished by the provision of a bearing member 2l, including an inner race 28, an outer race 29, and a plurality of anti-friction balls or rollers @il which are positioned between the two races, as is best shown in Figures l and 5.

The inner race 28 is formed integrally with a, boss ill provided with a locking screw or set screw 32, whereby the entire bearing member 28 is secured upon the shaft l l. On the other hand, the outer race 29 of the bearing member slidably engages the inner surface of the casing I2.

When the invention is placed in use, the cutter head it is simply applied to the ground and is rotated in any suitable manner, and as the depth of the bore increases, the casing I2 is lowered into the ground, substantially as shown in Figure 1- If desired, the lower end of the casing may rest directly upon the cutters I6, and since the cutting diameter is somewhat larger than the outside diameter of the casing, the latter will feed itself downwardly, so to speak, under the influence of gravity. Moreover, by virtue of this difference in diameters, that is, by Virtue of the annular space 33 existing between the casing I2 and the wall of the bore, loose dirt, and the like, may be washed to the ground surface.

Needless to say, during the boring operation the cutters I6 are retained in their radially projected positions by means of the springs 23, but after the boring operation is completed, the tool may be withdrawn from the casing by simply pulling the shaft II upwardly. During this action, the cutters I6 will be forced into their retracted positions by their engagement with the inner surface of the casing I2.

Of course, the bearing member 21 will effectively center and guide the cutter head I3 with respect to the casing, in addition to providing a bearing for the rotating shaft II.

If desired, the lateral wall of the cutter head I3 may be formed with recesses 34, so as to facilitate installation of the aforementioned pivot pins II.

It is believed that the advantages and use of the invention will be clearly apparent from the foregoing disclosure and accordingly, further description thereof at this point is deemed unnecessary.

While in the foregoing there has been shown and described the preferred embodiment of this invention it is to be understood that minor changes in the details of construction, combination and arrangements of parts may be resorted to without departing from the spirit and scope of the invention as claimed.

Having described the invention, what is claimed as new is:

In an earth boring tool, the combination of a vertical drive shaft having a pointed lower end, a cylindrical head secured to the lower` end portion of said drive shaft above the pointed end of the latter, the lower portion of said head being provided with a set of radially extending slots having open bottoms and extending outwardly from said shaft to points spaced inwardly from the lateral surface of the head whereby the latter affords wall portions of the outer ends of said slots, lower edges of said wall portions terminating substantially above the bottom surface of said head to provide lateral openings in the head constituting outward continuations of said slots, the lower end portion of said shaft being provided with recesses in register with the slots, horizontal pins provided in the head and extending transversely of the slots, a set of elongated cutters pivotally mounted intermediate the ends thereof on said pins and swingable from retracted positions in said slots to operative positions wherein outer end portions thereof project through said openings and their inner end portions are disposed in said recesses and supportably engaged by said shaft, upper edges of said -cutters abutting lower edges of said wall portions when the cutters are projected, and resilient means in said slots for urging the cutters to their projected positions.

GURNEY L. MICHAEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 449,613 Cameron Mar. 31, 1891 886,704 King May 5, 1908 1,183,630 Bryson May 16, 1916 1,369,959 Booker Mar. 1, 1921 1,502,463 Dunsworth July 22, 1924 1,510,222 Herman Sept. 30, 1924 1,658,125 Hutton Feb. '7, 1928 1,710,998 Rudkin Apr. 30, 1929 

